Hello David Nienhiser,
Thank you for posting in Microsoft Community forum.
For group policy change event, you will need to configure audit policy for Default Domain Controller Policy and group policy container.
For more information, please read link below.
How to detect who changed GPO - Spiceworks
I hope the information above is helpful.
If you have any question or concern, please feel free to let us know.
Best Regards,
Daisy Zhou